A 10-year-old boy apprehended last year after a flying to Texas as a stowaway was caught Tuesday trying to board another flight out of Sea-Tac Airport.

Semaj Booker was a short stroll away from a departing Southwest Airlines flight when, just after 6:30 a.m., a gate agent stopped the boy. Airport authorities returned the boy to his mother's home in Tacoma, from where he'd been reported missing.

Acknowledging that Semaj shouldn't have been able to reach a boarding gate, Baird said the boy had been through a security screening and did not pose a threat to passengers.

"The young man did undergo the proper screening process and at no time posed a security threat," he said, reading from prepared remarks. Baird said the agency will "take appropriate action with the employees involved" in the incident.

Semaj gained national attention in January 2007 when he hopped another Southwest flight, making it as far as San Antonio before airport workers caught on. As he did again Tuesday, Semaj told authorities then that he'd hoped to reach his grandfather's home in Dallas.

Semaj, then 9, took to the skies a day after leading police on a high-speed chase on state Route 512 in Lakewood. Police caught up to him after the car's engine failed and the vehicle struck a tree.

The boy sneaked through security at Sea-Tac and boarded a flight to Phoenix, then one to San Antonio. Airline workers in San Antonio took custody of Semaj when he tried to get a boarding pass by claiming his had been lost.

Semaj recounted his exploits last year on an episode of the "Dr. Phil" show.

"When I got to security, there was an announcement for a passenger to get his boarding pass. I went up and said that I was that guy."

On Tuesday, a ticket agent stopped the boy as he tried to board a flight to Sacramento at a gate on the airport's B Concourse, said Perry Cooper, a Port of Seattle spokesman.

Semaj told the gate agent he was traveling with a man ahead of him in the boarding line. When it became clear that the boy was alone and without a boarding pass, the gate agent notified authorities.

The child had already passed one checkpoint operated by TSA.

Cooper said it's against policy for unaccompanied children to pass through the checkpoint, but that the child was screened by security.

"There was no security breach," Cooper said. "They've confirmed that he went through the screening process."

Cooper said the boy might have told screeners he was with an adult in the checkpoint line, as he tried to do moments later at the boarding gate.

Semaj's family had reported him missing just before 3 a.m., a Tacoma police spokesman said. The spokesman said no auto thefts had been reported and that it remained unclear how Semaj ran away.

Calls to Semaj's relatives were not returned.

Port of Seattle police released the boy to his mother's custody. Cooper said the case is being referred to the King County Prosecutor's Office to determine whether charges are warranted; a Prosecutor's Office spokesman said the case had yet to be transferred Tuesday afternoon.